Bucillamine has a well-known safety profile and is prescribed in the treatment of rheumatoid arthritis in Japan and South Korea for over 30 years.

It is a cysteine derivative with 2 thiol groups that is 16-fold more potent than acetylcysteine (NAC) as a thiol donor in vivo, giving it vastly superior function in restoring glutathione and therefore greater potential to prevent acute lung injury during influenza infection.

[2] Bucillamine has also been shown to prevent oxidative and reperfusion injury in heart and liver tissues.

It is hypothesized that similar processes related to reactive oxygen species (ROS) are involved in acute lung injury during nCov-19 infection, possibly justifying the investigation of bucillamine as an intervention for COVID-19.

[3] On July 31, 2020, the U.S. Food & Drug Administration (FDA) has approved Revive Therapeutics Ltd. to proceed with a randomized, double-blind, placebo-controlled confirmatory Phase 3 clinical trial protocol to evaluate the safety and efficacy of Bucillamine in patients with mild-moderate COVID-19.